body {
    background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url('../img/yh/bj.jpg');
    background-attachment: fixed;
    background-repeat: no-repeat;
    background-size: cover;
}
.banxin {
    width: 1200px;
    margin: 0 auto;
}
a {
    color: #000;
    text-decoration: none;
    transition: 0.3 all l;
}
* {
    margin: 0;
    padding: 0;
}
.image-conten {
    border-radius: 20px;
    background-color: rgba(135, 207, 235, 0.502);
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
}
.box img {
    width: 300px;
    transition: 0.3s all linear;
    overflow: hidden;
}
.box img:hover {
    transform: scale(1.1);
    filter: brightness(0.8);
}

.box {
    width: 300px;
    height: 400px;
    background-color: rgb(36, 205, 228);
    margin: 40px;
    border-radius: 20px;
    overflow: hidden;
    opacity: 0;
    transform: translateY(50px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}
.visible {
    opacity: 1;
    transform: translateY(0);
}
p {
    color: #ffffff;
    margin-top: 30px;
    text-align: center;
    font-size: 25px;
    font-family: 'Noto Serif SC',serif;
}

.nav-1 {
    height: 500px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 50px;
}
.nav-1 input {
    width: 200px;
    height: 20px;
    transition: 0.4s all linear;
    background-color: transparent;
    border: 1px solid white;
    margin-bottom: 20px;
}
.nav-1 input:focus {
    width: 400px;
    height: 30px;
    border: 2px solid blue;
    color: white;
   
    border-radius: 10px;
    outline: none;
}
h1 {
    text-align: center;
    font-size: 80px;
    font-family: 'Noto Serif SC',serif;
}
.nav-conten {
    
    background-color: rgba(27, 149, 225, 0.575);
    height: 80px;

    font-size: 28px;
    font-family: 'Noto Serif SC',serif;
}
.nav {
    overflow: hidden;
}
.nav .left {
    float: left;
    position: relative;
}
.nav .right {
    float: right;
    
}
.right a span {
    transition: 0.3s all linear;
    margin-left: 20px;
    text-align: center;
    line-height: 80px;
}

.const-right-3:hover ~ .nav-2 {
    height: 150px;
}

.nav-2 {
    background-color: white;
    height: 0px;
    transition: 0.4s all linear;
    border-radius: 20px;
    overflow: hidden;
}

.nav-2:hover {
    height: 150px;
    cursor: pointer;
}

.nav-2 li:nth-child(1):hover {
    color: #48ff00;
    filter: brightness(0.8);
}
.nav-2 li:nth-child(2):hover {
    color: #0031c5;
    filter: brightness(0.8);
}
.nav-2 li:nth-child(3):hover {
    color: #00bfff;
    filter: brightness(0.5);
}

.nav-2 li:nth-child(1) {
    height: 50px;
    line-height: 50px;
    text-align: center;
    background-color: rgba(0, 0, 255, 0.635);
}
.nav-2 li:nth-child(2) {
    height: 50px;
    line-height: 50px;
    text-align: center;
    background-color: rgba(178, 18, 98, 0.703);
}
.nav-2 li:nth-child(3) {
    height: 50px;
    line-height: 50px;
    text-align: center;
    background-color: rgba(96, 173, 32, 0.58);
    
}

.right a:hover span {
    font-size: 30px;
    background-color: rgba(26, 133, 221, 0.612);
    border-radius: 10px;
    width: 100px;
    height: 20px;
    padding: 10px;
    color: rgba(37, 97, 183, 0.863);
}
.center-h1 {
    font-size: 50px;
    display: inline;
    margin-left: 320px;
    text-align: center;
    line-height: 80px;
}
.logo {
    margin-top: 10px;
    width: 50px;
}
.left div {
    position: absolute;
    background-color: red;
    top: 10px;
    left: 30px;
    font-size: 18px;
    border-radius: 20px;
}
.left h2 {
    display: inline-block;
}


.float-conten {
    margin-top: 100px;
    height: 700px;
    background-color: rgba(135, 207, 235, 0.502);;
    border-radius: 20px;
    overflow: hidden;
}

.float-conten div {
    text-align: center;
    line-height: 100px;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background-color: #00bfff;
    float: left;
    margin: 10px;
}

.float-conten div:nth-child(2n) {
    background-color: #ff0000;
}